Communication networks include a large number of interconnected components that enable a UE (user equipment) device with network access to communicate with other such devices located within the network coverage area, and with devices connected through other networks as well. The architecture of any communication system in modern use is generally somewhat hierarchical, that is, widely-disbursed access points allow users to connect with a more centralized core network, which is able to route the voice and data information involved in a great many communication sessions.
For example, a wireless network includes many access nodes, typically antennas connected to BTSs (base transceiver stations), distributed over the network coverage area. A network subscriber using an appropriate device can establish communication with the network though one of these access nodes. During a communication session, voice and data information transmitted to the access node is then relayed to a core network for routing to its destination. Information destined for the subscriber is sent to the appropriate access node for transmission to the UE device.
A wireless network coverage area is often divided into cells, or relatively-small geographic areas having (normally one) antenna for radio-frequency communication with UE devices located within or near the cell. The advantage of a cellular network is that mobile phones can transmit at relatively low power to a near-by antenna, which conserves UE battery power and also allows the reuse of the same frequency channels in non-adjacent cells separated by only a relatively-small distance.
For efficiency, a number of access nodes may be grouped together into an access network, which aggregates the voice and data traffic associated with many UEs for communication with the core network through one or a limited number of network nodes. In a wireless network, this process is sometimes referred to as wireless backhaul. There are several network architectures that may be employed for constructing the access network for backhauling.
Ethernet is one such architecture. An Ethernet network is one that is configured and operated according to the standard IEEE 802.3 and a number of related standards. For example, IEEE 802.1Q and IEEE 802.1AD specify the configuration of virtual bridged local area networks and provider virtual bridged local area networks, respectively, including VLAN (virtual local area network) tagging, and IEEE 802.1D specifies the configuration of MAC (media access control) bridges, including the use of STP (spanning tree protocol).
Ethernet networks may be organized or configured into “rings”. A ring configuration is formed by examining a set of Ethernet nodes capable of routing information traffic, and determining a manner of routing that provides a pair of redundant paths from an originating node to a destination node. Note that in this sense, the term “ring” is a general topological reference, but does not necessarily connote a specific physical layout. Nor does the term imply that traffic is ordinarily routed in a loop or circular path. The nature of a ring, as that term is used here, will become more apparent in light of the exemplary embodiments described below.
There are different ways for implementing Ethernet configurations in the wireless backhaul context. One way, for example, is to provide a plurality of suitably interconnected bridges running a routine referred to as STP (spanning tree protocol). While STP is relatively cost-effective, in the event of a fault, that is a breakdown somewhere in the configured ring, the recovery procedure it provides may be too slow to qualify as carrier-grade operation. Another example is a RPR (resilient packet ring) scheme, which provides better fault protection than STP but has not proven cost-effective and probably for this reason has been implemented on only a limited basis.
Needed, then, is a solution for wireless backhaul aggregation networks that is not only acceptable from a cost perspective but also provides adequate load balancing and fault protection in operation.